It has been the practice to duplicate individual hardware units used in the switching or transmission of digital signals if failure of a single hardware unit could cause the failure of a predetermined number of digital signal channels. That is, there must be a backup hardware unit which can be switched to in the event of such a hardware unit failure. In known hardware protection switching arrangements, the switching of digital signals from one hardware unit to the other is achieved by employing relays. In such arrangements, signal loss is detected and the signal is redirected to a standby unit. A problem with the relay switching arrangement is that the customer communication traffic is interrupted for a significant interval. This interruption could cause calls to be dropped, which is undersirable. Even if the call is not dropped, the relay switching causes so-called glitches or hits in the digital signal transmitting the customer communications traffic which may cause an alarm condition. For example, the glitch could propagate as a bipolar violation or the like.